When working with an unpublished theme or better known as a draft theme, you can send out a Share preview link which allows anyone who has the link to preview your work/site. Share preview links expire after a certain number of days and are randomly generated by Shopify.
In the Theme Editor, click on the ellipses (three dots) icon at the top of the Theme Editor to view theme actions.
When the new preview window appears, choose the green Share preview button at the bottom of your browser
Click the Copy link button to copy the address to your clipboard
Send us that link, paste it from your clipboard