You're asking some decent questions.
You can do google ads, facebook ads, tiktok ads, etc.. you name a platform and they will have system for you to advertise as all these sites make money through mainly one channel - advertisements. And because of that they want to be able to make it easy for you to not only get on that platform, but to target the demographic you want as well (this is why facebook was so successful, you gave them exactly who you are/your interests, so advertisers were willing to dish out more money to them).
I would recommend hopping into one of the platforms and looking around. Then watching a youtube or udemy video on how to optimize your ad campaign.
WARNING: These systems make it very easy to part you from your money, so if you are going to spend money, start small and set daily limits. If you don't do it right, you can easily see 10k+ go away in hours.