You can enter your contribution the say way if you did have a 1099SA. Follow the steps in this TurboTax link to enter your HSA contribution:
https://ttlc.intuit.com/questions/2766470-where-do-i-enter-my-hsa-contribution
HSA custodians are required to furnish tax documents. Check your online account and confirm one isn't available for you. Also, it is very common for HSA custodians to provide tax documents later in the tax season. In the meantime, use your HSA account statements to total your contributions and distributions.
