Website, web app, or mobile app
Pick the smallest thing that lets the customer finish the job.
Choose a website
Choose a website when people need to understand the business, read the offer, and contact you. Most local companies need this first.
Choose a web app
Choose a web app when people log in and do a task: book, order, update a record, or run a team. It lives in the browser and does not need an app store.
Choose a mobile app
Choose a mobile app when the phone itself matters: alerts, a camera, or an icon people open every day. If a website would do the same job, start there. It is faster to launch and easier to change.