Wireless Keyboard gone weird with new computer

If this is a fairly recent rechargeable Apple Magic Keyboard, you can plug it into the Mac with the charging cable and it should behave as a wired USB keyboard. Does the problem persist if you do that?

Can you try the keyboard with another computer?

Reboot your Mac. Do you have the same problem after that?

Could be the keyboard is failing.

digibeta2012 wrote: no spacing or delete and some letters are missing.

What letters exactly are missing? Make sure that in your Accessibility settings you have Full Keyboard Access and MouseKeys turned OFF.