The Canadian Federal Government has yet to finalize the regulatory framework for the expanded use of cannabis beyond people with medical needs. This framework will establish such matters as the legal age for use, how the product can be purchased, and where it can be used.

The strains, potency, product offerings, method of use will differ for medical and recreational use.

While the cultivation process for the plant itself may be the same, when the plant is grown for medical use, it must be grown under license by Health Canada which requires strict adherence to good production practices, sanitation guidelines, and pesticide use, among other requirements. Each batch must be tested prior to sale. 
A client who wishes to access cannabis for medical use must have a prescription from a healthcare provider and be approved by Health Canada, either to purchase
or grow cannabis.  A licensed producer then must confirm the client’s identity and circumstances, and keep records of the client’s purchases and shipments.
There are monthly limits for the quantity of shipments. Medical-use clients may have some options to have their cannabis costs subsidized or paid for by a benefits provider, and they may also be eligible to deduct these medical expenses when filing income tax returns see FAQ: Will my medical plan pay for it?