I have an Asus ZenFone 5, and it doesn't have the option "move to memory card", but I'm out of free space, how do I force the app to move to the memory card? I didn't find any tutorials
No I believe that is not true, at least on my wife's Samsung A71. You had to do it individually in settings, per app though. I believe under developer settings there is a toggle to force apps to SD card as well. We moved a few games and set the camera to store pics on the card as well.Android stopped allowing apps to move to the SD card several years ago as it would cause all kinds of problems. SD cards read and write at a slower speed than phone's internal storage. It would cause cards to fail and then apps installed into the card would no longer work properly.
If you are out of space maybe you could backup your data to the cloud, like Google Photos/Google 1 or other services.