The menu has Downloads in Firefox 81, but I don't think that was introduced yet in Firefox 79-80.

By default, Firefox downloads to the Downloads folder, so you probably need to view that to find your downloads for now.

Apologies for not mentioning that I'm talking about the android ver. Of Firefox, and actually I'm looking for the button to engage into pausing and resuming the downloads

Hi

If you long press on the file or link that you wish to download, you should see the option to do so. This is in Firefox for Android 81, so if you have not already, I recommend that you update.

Downloaded files can be found in the Firefox for Android menu under Downloads.

I hope that this helps.