[axilmar]

Requirements always exist in a project, even if they are not written.

And how they cannot exist, since the only reason a program is written is because of some need...

And since requirements always do exist, they better be in written form, so as that they can be referenced, tested, discussed etc.

In previous projects, JIRA was used. In the current project, an internal tool is used, pretty much similar to JIRA.

In some older projects, a simple Word document was used and an Excel sheet for tracking progress.

Writing a requirement should be simple enough: it shall either define things, or describe processes and their side effects.

It is better to have a dedicated person to write them, because the wording and style of requirements should be consistent, and the person that writes them will gradually be more and more experienced in writing better requirements.

Having good requirements makes it a lot easier for developers to write the required programs.