Unfortunately, the Apple Developer account is not free. You need to pay money for a year. Two types of apple developer accounts are served by Apple. These accounts have different prices.
The normal one called the individual and you need to pay 99 $ in a year.
The other is called the business account and you need to pay 299$ for every year.
These accounts are very useful if you respect the apple developer's contract. But some people use these accounts for bad things and the apple ban these accounts immediately.
Sometimes Apple sends you an email for new changes on contract and you need to approve them on their developer admin pages. Also sometimes there are many changes in billing systems.
If you don't update your apps in the timeline defined, your apps may be a pause in AppStore. You need to make your app up to date for release on AppStore. But sometimes you can see apps about ancient times. There are few. Apple makes them offline from time to time.
For buying the Apple Developer account you can use the apple developer website from this link. Also if you need some advice for yourself, you can connect with me from social media.
There are some different features in the business account. Maybe if you thing more professional things. You need to buy a business one. Because in individual accounts, you can't set any company name. In this account, it is your name and surname. But in a business account, you can use your company name like Uber, Facebook or Spotify.
If you want to look more professional you need you to use this way. Also with this account, you need an active company and duns number for register.
There are all I know for developer accounts.