DOCUMENT I COULD EDIT AND SUDDENLY I COULDN'T

The most awful useless form filling anything I have ever come across in a million years

Why does anyone anywhere use it?

Snaity draining despicable reprehensible 

Why does every bloody school use it for their forms???

WHY OH WHY?

I am about to complete an application for a special needs senior role because I cannot be bothered to spend another nano second of my life on it.....

(remarks removed by moderator)

Yes, that is normal. Signing a form locks it from further changes. However, since you signed it you can remove the signature. Right-click the signature field and select Clear Signature, and the form should revert to normal, after you save and re-open it.

After signing the form is locked.