Can i migrate keynotes from iMac to Macbook Pro?

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If you purchased it in the App Store or a DVD, you can install it on all your Macs for free, so you can migrate it to the MacBook Pro

Do you mean the program itself? If so then if it was bought from the Mac App Store just logon to the MAS with the same Apple ID you used when you bought it and redownload and install on the new Mac.

If it was bought on DVD then get that DVD out and install in on the new Mac then run Software Update to bring it up to its most current version.

If you mean the Keynotes you created then just copy them over your LAN from one Mac to the other.