Why does it make some commands which I didn't input?

On rare occasions it's possible for a misbehaving or malevolent app to cause this kind of behavior, but in most cases it turns out to be a phenomenon called ghost touch. It's caused by damage to the digitizer that results in electrical noise on the signal lines being interpreted as touch inputs.

You will definitely want to eliminate software as a possibility; start with restarting the phone, doing a hard reset, booting into safe mode and as a last resort restoring the phone to factory settings. If it is still having issues after all that, then the problem is almost certainly in the digitizer.

Since the digitizer is bonded to the display, the fix for a bad digitizer is to replace the screen. iFixit doesn't have a guide for your particular phone, but the Spanish site Nadie Me Llama Gallina has just what you need.

Manuales / Honor 8X / screen - Nadie Me Llama Gallina

The screen itself seems to be readily available and since this is an older phone using LCD technology, the replacements are pretty inexpensive. I'd suggest starting out with sites like Amazon, eBay and AliExpress, but there will be many other choices to be found on a general internet search.