We currently don't offer to mount the poster and frame together before shipping to customers. We have chosen to do so to be able to expand our footprint of where we have poster+frames capabilities and be fast and effective in serving your customers
However, based on your suggestions we will soon add this option to our offer. We hope to have the official launch in September 2022!
Please stay tuned for more information!
For the moment, if you are unsure about how to mount a poster into a frame, you can read more here: How do I mount a poster into the frame?