Essay
MLC vs HFA: Which One Does What for Songwriters?
The MLC and HFA both collect mechanical royalties for songwriters, but only one is automatic for US streaming.
The MLC handles US interactive streaming mechanicals under the MMA blanket license. HFA remains relevant for downloads, physical, and some publisher-administered catalogs.
Found Royalties files both. You should not have to know which envelope a particular play belongs in.