How are comments made?

hello! I have a doubt.
When we heat up a code… Can it be done in any way? Or on what occasion is each one used?

// comment
/*comment
*/
\<!--comment-->

How do you ‘heat up’ a code? I don’t know what you mean.

Each programming languages have their own ways of doing comments. If comments can be done in multiple ways, just pick one and be consistent.