A "stock power" a.k.a. a "stock transfer" instrument is the equivalent of a deed to real estate, a bill of sale to personal property, or a signed certificate of title to a vehicle. It effects the change of ownership.
A "stock purchase agreement" is a contract in which a buyer agrees to purchase stock from a seller, but a stock purchase agreement has to be performed by executing a "stock power" or comparable instrument, in much the same way that a real estate purchase agreement sets circumstances under which a deed to the real estate will be signed at a closing, but does not actually itself transfer the real estate.
I am wondering if the blank here is the place where I would
communicate somehow that I will be exchanging IP for the shares.
The stock power states: "FOR VALUE RECEIVED and pursuant to that certain Restricted Stock Purchase Agreement between the undersigned . . .", but the value received, if it were IP, could be described on the face of the stock power for instance stating "FOR VALUE RECEIVED, including a transfer of Patent #84847474 to the Company, and pursuant to that certain Restricted Stock Purchase Agreement between the undersigned . . ."
But, it would be more customary to set forth the nature of the consideration in the "Restrict Stock Purchase Agreement", and to be non-specific in the stock power itself.
Also, is this the "stock purchase agreement" I have been needing to
No, the stock power is not a stock purchase agreement. A written stock purchase agreement is optional, however (although you should remove any reference to it in the stock power document if there isn't a written stock purchase agreement). An agreement to buy and sell shares in a company is not subject to the statute of frauds (i.e. to a requirement that it be in writing) in any U.S. state of which I am aware (except in New York State where the "equal dignities rule" requires that transfers of stock in corporations owning real estate is subject to the same formalities as transfers of real estate), although that is not the rule in some non-U.S. jurisdictions.