Q: need ... activate ipad  ..... this ipad is linked to an apple id.

It sounds as if you are talking about a previously owned iPad.  This iPad is Activation Locked - meaning, the previous owner did not release it.  That must happen in order for you to be able to use it.  If the Activation Lock is not released by the original owner, nobody can help you.

Contact the original owner or get a refund.

Here is more information:

Find My iPhone Activation Lock - Apple Support