Where did you found it?

Where you found it?
Where did you found it?

Do we need to add “did” in front of the sentence above?

Yes, and you need to say “find”, not “found”.

“Where did you find it?”

Thanks.

Also know that ‘found’ can be used with the meaning of ‘establish’, ‘start’ etc. Look at these examples:

Who founded that movement? Where did they found it? Was it founded in Europe?

So, these are two different verbs: find - found - found; found - founded - founded.

Thanks for that catch, Anglophile.

You’re welcome, Luschen. Please don’t mistake me. It was added for Tomasso.