A Salesforce Administrator is the person who configures the platform so that the business can run on it without writing code. The day-to-day work clusters around four areas: user management, data, automation, and governance.
User management means provisioning users, assigning licences, managing profiles and permission sets, and resetting passwords. Data work means importing and exporting records, fixing duplicates, building reports and dashboards, and looking after data quality. Automation means building flows, validation rules, approval processes, and email alerts so manual steps disappear. Governance means managing change sets or deployments between sandbox and production, monitoring storage, watching the setup audit trail, and reviewing release updates.
Most admins also act as the first line of support for users — if a sales rep can't see a record, the admin checks the sharing model; if a screen looks wrong, the admin checks the page layout or Lightning App Builder. On a typical day an admin will field a few support tickets, ship a small enhancement (a new field, a tweak to a flow), and spend the rest of the time on a longer project like a migration or a new app rollout.