Auto Sort New Entry

Hi everyone!

I'm sure you get asked this often but I can't find what I'm looking for on the internet so I'm asking and yes I'm a new-be! No laughing

I have a spreadsheet of 9 cells across A4 - I4 (white)and around 900+ down (but will be adding to this number and that's where you all come in...). It'a a list across of company names, legal name, street address, city, state, zip, phone numbers, website and business type. I want to be able to pick a cell like A3 (green) to entering all new info across then click a cell preferably A1 (blue) to be formulated to "Auto Sort" where it will put the row alphabetically down where it below...simple right? I worked off a spreadsheet at my previous job and can work within it, but have no idea how to create one?

Can you help?

Nardi