"Do I need to bring the actual letter or can I just show the ID card?"
Yes, your medical marijuana recommendation letter should be accepted if the dispensary adheres to California law. Upon approval, you can immediately print a PDF copy of your letter from your HelloMD account. You can find it by going to your "medical case" while logged into your HelloMD account, or by tapping "medical" if you are in the HelloMD app. The photo ID card you receive in the mail is merely meant to be a convenience, and you should keep the actual letter with you at all times. After you have presented the actual letter and registered with a dispensary, they may let you return with just the photo ID card, but this varies by dispensary/delivery service.
Most dispensaries will accept the PDF copy of your letter, although some may request an embossed version (there is no basis for this in CA law, it is an individual requirement of certain dispensaries). This embossed letter will be mailed to you via USPS first-class mail along with your ID card; allow 3-5 business days for it to reach you
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