More detail
The slow path is treating registration, hardware and software as three separate projects. The fast path bundles them, so you are selling compliantly soon after you start.
Make sure your KRA PIN is in order, then get set up on an eTIMS-ready system. From there, every sale issues a compliant invoice without extra effort.
Related questions
What do I need before I start?
How do I check I am ready?
Veira gives Kenyan shops one calm app for selling, M-Pesa, KRA eTIMS and stock, with a free terminal. Book a demo and see it set up for your trade.