A preliminary talk with the planning dept. would be the first step, but a few things to consider as well.................
Running a small business from home is generally allowed, but this would need a planning application. It's what they call a "material change of use". The "class of use" would change from domestic to business.
Check that your mortgage doesn't exclude business use.
Check up on fire regulations. Shops have Joe Public roaming around inside them. That can throw up different fire precautions.
Ask the planners if your area can contain business use. It may be designated as residential only.
Alterations to include a shop front can be costly.
Business rates and insurance will likely be very much higher.