When you Create an account verified and then you can start your promotion on all social media platforms by placing a link in the bio text that links to your page, Reddit is a popular platform to do this, for example, Twitter and Instagram also works fine, What also works very well is, find a popular model on social media and ask if they want to share your profile link on their profile so that you appeal a large audience at once, there are also special Telegram groups where models agree with each other and make proposals to promote each others profile to create more fans, Keep in mind that there are many profiles that pretend to be promoters of OnlyFans, on Instagram for example you see this a lot.
But in reality these profiles have almost no followers, but the asking a high fee for a so called promotion massage,this promotional message will be placed on an Instagram profile or story of Instagram with almost no followers at all, so this is really no uses at all and bad for your time, these profiles send you a private message, they send it from an account with a lot of (fake) followers so that it looks like you are buying a promotion massage for that profile, with the high number of followers and that does not happen and then you have paid for nothing, don't fall for this!! automated messages that are sent an mass message to many profiles at the same time, in the hope that someone will kick in so don't get in to that, on OnlyFans make sure your address is verified.
On the other hand actually all social media platforms are good for promoting your profile, consider that you place a link in the bio of your social media profile that refers you to your profile, Also think of Reddit, Tumblr Pinterest Twitter Facebook Instagram Snapchat and all the other platforms the out there these days, Reddit is a very good example to do this, because on Reddit there are even groups where you have the option to promote your profile, in certain groups related to the topic you would like to promote, currently there are many large groups with many subscribers who are all about this on reddit, so this is an ideal place to promote your profile.
It is also possible to promote your profile on Telegram, this again reached a large group of people that follow groups to receive and share information about this, make sure when you are getting promote an account that it is an legal account.
If you are planning to post sexual content it is also useful to post your profile link on one of the more popular porn websites of this moment such as Pornhub and Xhamster, Of course you are not allowed to sell photos and videos from another creator on your profile without permission from another creator because of course copyright rights are involved.