1 (friend's name+Happy 20th birthday+I love you forever) These things are all written on the note (the contents can also be filed by yourself).
It is best to take a selfie with a digital camera or mobile phone. If it's not enough, bring a good buddy.
Go around the streets looking for signs that match your note. Remember that there can only be this word and your big head in the camera (remember that there can only be one word on each sign note).
Go home and edit it yourself or find a wedding company to help you match romantic music and send it on CD.