whoa i did not expect such an answer
thank you for letting me explain (roghly)! i can not give you proffessional advice on licensing, as that could be counted as legal services. but i would recommend you take a look an the creative commons licensing database. or if it should be more of a technical license, tldrlegal.com
is a good first go.
what you will need, or well, what youre target group would probably need is something
* written (digital and not personalized is fine in most cases)
* statement that either [customer name] or "whoever obtains this license" is allowed to use your work
* for commercial use (you can leave out this option if providing a license "to all" and then put this option in for individual requests)
* and probably with the possibility to change, modify, alter,... the music, if youre okay with this (might come in handy if using sequences of different songs in a row). you can give this option more thought on what would be ok for you and under what conditions
* stating name is no problem with any licensing area i know of, that does not provide a problem at all as far as i know, but you might want to ensure, that people really do state your name.
whatever you do, please do not write a license yourself, but use premade licenses offered by vreative commons, fsf, mit etc. as licenses are contracts (and, except for public-domain-equivalents) rather complex ones. it also needs to consider different handlings of licensing around the world, thats why it is best to use a premade, legally checked, license.
and yes, youre idea with the statement would work i guess (did not check thoroghly though), and for giving out a license after somebody reached out, my comment (the senteces above) could be useful. i would include, that the given out license will not contain any financial charge, since otherwise some people might not consider using it. that is, if you don want to give it out for free of course, you can set the rules to your liking!