A domain name matters less for ranking than almost anybody will tell you, and more for one specific thing that hardly anybody mentions. Let us deal with the real decision first and the folklore second.
The one choice that genuinely has consequences
Nigerian addresses ending in .ng, including com.ng and org.ng, are country-code domains. Google's guidance on multi-regional sites says that country-code top-level domains are tied to a specific country and therefore provide a strong signal to both users and search engines that a site is explicitly intended for that country.
That is the upside, and for a business trading only in Nigeria it is a real one. Google lists the advantages of a country-code domain as clear geotargeting, server location becoming irrelevant, and easy separation of sites.
Now the part that gets left out. Google lists the disadvantages in the same place, and one of them is that a country-code domain can only target a single country. Google also states the tradeoff plainly: targeting a single country can improve your page rankings in that country, but at the expense of results in other locales or languages.
So the decision is genuinely about your ambitions, not about SEO points. If you serve Lagos and you always will, com.ng or .ng is a sound choice that quietly tells Google and every customer exactly who you are for. If you sell anything that might reach buyers in Ghana, in the UK, or anywhere in the diaspora, a .com will not fight you about it.
One correction worth making because it is technically important. Google treats some country-code domains as generic because people use them that way, including .io, .co, .me and .tv. Nigeria's is not among them. Google's rule is that unless ICANN lists a domain as a country code, it is treated as generic, and .ng is listed as Nigeria's country code. So the country signal is real and it applies to the whole .ng family.
What is actually available, and who can register what
NiRA, the Nigeria Internet Registration Association, manages .ng under authority from NITDA. It does not sell domains itself. NiRA operates what it calls the 3R model, registry, registrar and registrant, and states that it does not register domains directly for end users. Every registration, renewal and transfer goes through an accredited registrar, and NiRA publishes the list.
NiRA's policy divides the namespace into open and closed. The open ones, where NiRA states it imposes no restrictions on your status as an applicant, are com.ng, org.ng, net.ng, mobi.ng, name.ng, i.ng, and .ng itself.
Each open extension has an intended purpose, and it is worth knowing these are intentions rather than gates. NiRA describes com.ng as intended for commercial purposes and fully open since 5 July 2008. It describes org.ng as intended for not-for-profit or public service enterprises. For net.ng it says registrants include internet service providers and telecoms infrastructure providers, and then says explicitly that the extension is open to other registrants including businesses and individuals notwithstanding that they are not ISPs. name.ng is the exception that is enforced by definition, because registrants must be and remain natural persons.
On enforcement generally, NiRA's policy is unusually candid: it states that it will take no action in respect of registrations that do not comply with the charters, while reserving the right to ask for information about your legal identity.
The closed extensions do have real gates. edu.ng is reserved for tertiary institutions accredited by the relevant authorities, and requires both registration under Nigerian law and approval from the accreditation body. sch.ng is for primary and secondary schools approved by government, and NiRA allows each approved school a single registration. gov.ng is limited to governments and their ministries, departments and parastatals. mil.ng is closed, with verification conducted by NITDA.
A note on the short form. A second-level address like yourbusiness.ng is a real option and NiRA's own monthly reporting shows thousands of these registered alongside the longer com.ng form. The policy document and current practice do not read identically on how these are allocated, with some parts describing premium and auction routes, so ask a registrar what is actually available for the name you want rather than assuming either way.
The rules you can actually break
These are registry rules, which means they are enforced at registration rather than being advice. From NiRA's policy: only letters a to z, digits 0 to 9, and hyphens are permitted, and NiRA does not currently offer internationalised domain names. A name cannot begin or end with a hyphen. It cannot consist only of digits. The whole address including the extension caps at 64 characters. Names are allocated first come, first served, and are not case sensitive.
Two specific rules catch people out. A one or two character name is not available under the ordinary process, only by auction. And your chosen name cannot duplicate an existing extension string, so an application for something like org.com.ng would be rejected.
Now the folklore, one piece at a time
Keywords in the domain. Google has published exactly one relevant statement, from its blog in July 2015, and it concerns the extension: keywords in a top-level domain do not give any advantage or disadvantage in search. On keywords in the name itself, the part before the dot, Google has published nothing in its current documentation. Not that it helps, not that it hurts. Anybody telling you that putting your service and your city in your domain will lift your rankings is telling you something Google has never said. Google's only keyword-in-address guidance concerns page paths, where it does suggest including useful words.
Hyphens and numbers. Google publishes nothing about either one in a domain name. The hyphen advice you have read, which is genuine, is about page paths, where Google recommends hyphens rather than underscores to separate words. Every example Google gives is a path. For the domain itself, the only real constraints are NiRA's rules above. Use a hyphen if you must, avoid it if you can, and understand that you are making a decision about whether people can say your address out loud rather than a decision about search.
The new extensions. Google's position is that its systems treat new generic extensions like .shop, .store and .agency the same as .com and .org. It adds that extensions which look region-specific are still treated as generic, consistent with how it handles .eu and .asia. By that rule .africa is a generic extension and not a regional signal, whatever it looks like. Branded extensions get no extra weight either, and Google has said so directly.
Setting a target country in Search Console. Do not go looking for this, because it is gone. Google has deprecated the International Targeting report and states that the ability to target search results to specific countries using Search Console country targeting was determined to have little value for the ecosystem and is no longer supported. Google continues to support hreflang tags on pages. If you are following a guide that tells you to set a country in Search Console, that guide is describing a screen that no longer exists.
Two practical points before you buy
Pick one form of your address and stay on it. Google treats the version with www and the version without as different, and http and https as different again. Search Console properties and sitemaps are specific to the exact form. Google removed its preferred domain setting in 2019 and now treats this as a canonicalisation matter, which you handle with redirects and canonical tags rather than a switch. Choose at the start and you will never think about it again.
Choose for the long term. Google's own advice on changing domains is that it treats the change like any other site move, that it takes time to be processed, and that outside search there is the separate problem of people expecting your email addresses to keep working. It concludes that it is generally best to choose a domain that will fit your long-term needs. A domain is one of the very few decisions in this whole field that is expensive to reverse, which is a good reason to spend an extra day on it and no reason at all to spend a month.