guys i have Etherium private key was saved in notepad accidently my kids press some alphabet and first 20 digits missing and i have saved it without notic can anyone please help me to recover if its possible
Unfortunately not.
You would have been able to restore a few chars, but definitely not 20.
By the way, if you don't have an offline backup (not stored on your computer), you don't have a backup at all.
Any incident affecting your computer (electrical short, ransomware, .. ) could have lead to a loss of the private key.
Storing a backup on the same device as the wallet is not a backup at all.