To find your ID on DoorDash's customer facing website:
Navigate your your DoorDash storefront
Look at the URL (the web address on your browser)
Note the string of numbers at the end of that address - that's your Store ID!
In the example below, the Store ID is 1150991
To find your Store ID from DoorDash's Merchant Portal.
Log into the DoorDash Merchant Portal
If applicable, click "Stores" from the navigation bar and select the relevant location
Check in the URL bar for the ID after the "?store_id=" string.
In the example below, the Store ID is 1150991