How do you document an API?

Question

Documentation

For example, we are writing a certain program, and of course, everything is commented in the code. Separately, we can structure all available interfaces and data types that can be accepted, for example, in gedit, notepad, textmate or somewhere else. But, are there services or solutions that help with this? I want to organize the documentation beautifully and in an orderly manner. Also, it would be great to ask how you solve this issue.

Answer 1

for internal consumption - we generate documentation on comments.
for external consumption - the first item is brought to the desired state by special people .