DHCP over 802.1Q VLAN

I have a switch with 802.1Q VLAN setup, where I want to use a mikrotik router for DHCP. If I have a DHCP server on a tagged VLAN interface, this should work fine going through the switch? Have an IP phone not picking up DHCP, I’ll try a factory reset of the phone

Don’t forget to enable cdp/lldp on this port.

How is the iPhone getting to the network? I assume there is a WiFi AP in there someplace. Does it know how to process a VLAN?