Tap head

The grub screw to the tap is usally to the back of the tap or under the lever opperating the the tap if this not the case the to remove the tap head if there is a spindle to the tap head try unscrewing the spindle if this do not unscrew or there is no spindle the the tap head usually can be remove by pulling it off

Usually to remove a tap, you need to unscrew the bottom screw

What I would need to do is use an Allen wrench to remove the set screw from the faucet head.

Most tap head's have a grub screw. These are usually located at the back of the tap. Sometimes they are missing and the tap is just stuck in place

If you're struggling to remove the head of your bathroom tap due to a hidden or stuck grub screw, there are a few methods you can try. First, attempt to use a flat-bladed screwdriver to remove the grub screw, gently tapping the end of the screwdriver with a small hammer while turning it. If that doesn't work, apply a penetrating lubricant like WD-40 to the edges of the grub screw, let it sit for about 15 minutes, and then try turning the screw. Another option is to use a screw extractor, which involves drilling a hole into the center of the stuck screw and using the extractor to remove it, but be aware that this method will ruin the grub screw. If you're still having trouble, consider using a ball end hex key, which can sit further into the grub screw, or pliers to hold onto the top of the key for extra leverage. If you're not comfortable performing these steps yourself, it might be best to call a professional plumber to avoid causing any damage to your tap.

There is normally a cap in the middle of the tap, pops off with a thin screw driver, under there there is a screw, undo the screw then the head should come off.

Tap must have cover on which normally screws of anticlockwise

It's mist likely at the back of the handle a cap will covering it

If you can post a picture of the tap I may be able to assist.