Custom Phrases & Keywords in AdWords Express
Keywords are part of AdWords, not AdWords Express. And search phrases are populated automatically, which one of ideals of AdWords Express. If you are looking to control your account and manipulate it... you may want to use AdWords instead.
Also, you can contact support and see what they can do for you with your request, as they can assist you further. Call 1-866-246-6453 Monday-Friday, 9:00 am to 8:00 pm (EST).
All the Best,
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