If it's more than just you who accesses the Shopify admin, you can setup "Staff Accounts" to give your employees access to the Shopify admin, instead of sharing the same username and password with everyone.
To add staff accounts:
Sign into your Shopify admin (as the account owner) > Settings > Account > Click the "Add staff account" button, within the "Accounts and permissions" section.
Put in the staff member's first name, last name, and their email address. If you want to limit what they have access to, uncheck the box for "This staff account will have full permissions." This will cascade some options, and you can check-mark only the parts of the admin that you want them to be able to see and be able to edit.
Once you're happy with the permissions you've granted, click the "Send invite" button, and the staff member will receive an email (to the address you listed for them) with a link they can click to set their own login password.
Need more help with this step? Check out Shopify's help docs for staff accounts by clicking here.