I installed some Add-ons for Firefox but there are many icons on the same row as the address bar.
I can hardly type web address on Firefox
How do I hide some Add-ons, like how I can hide some extensions icons on Chrome?
Right click on an empty area of the toolbar e.g. just to the right of the address bar. A menu should appear with Customise... in it.
If you can't find an empty area then any icons that don't have special right click behaviour such as the Show History icon should show that menu.
Select Customise... then drag any icons you want off the menu onto the customise page or onto the overflow menu are that appears. Click the Done button on the bottom right to finish and make your changes permanent.
Right click on an add-ons icon and select "pin to overflow menu".
You can drag to extend address bar size and hide some extensions on Chrome, but Firefox doesn't have this drag function. Right click and select customise to batch drag items to overflow menu. You can also remove the flexible spacers and use compact density to make more room for the address bar.