Membership in SIGMAA QL requires membership in the MAA, plus annual SIGMAA dues ($12 in 2018).

If you wish to add SIGMAA QL at the same time you renew your MAA membership, the most direct way is to use the MAA renewal process. You can also join a SIGMAA through the MAA website at https://www.maa.org/community/sigmaas/joining-a-sigmaa.