Driving a manual vehicle needs a bit more practice and involves a few more steps than an automatic vehicle. Because of this many drivers prefer to learn in an automatic vehicle - especially if they want to pass their driving test faster.
Manual cars have an accelerator, brake and clutch so you change gears yourself by co-ordinating the accelerator, clutch and gear lever. Automatic vehicles only have an accelerator and brake - the car changes gears for you. This makes learning to drive easier and generally means you will reach test standard with fewer driving lessons. An automatic car may be easier to drive; especially on more busy town roads and whilst manoeuvring. If you are having challenges managing the gears or stalling, then taking an automatic test could be a better, quicker and cheaper option.
If you pass your test in a manual car, your driving licence will allow you to drive both manual and automatic vehicles. If you pass in an automatic car you can only drive an automatic vehicle. You can always go back later and take your manual driving test - you don't have to redo your Theory Test or necessarily take lessons with a Driving Instructor. You will already have the driver skills required to keep you safe - you'll just need to master clutch and gear skills which can be done with a friend or family member in a manual car. The normal learning rules will still apply for the supervising driver; L plates and insurance.
Automatic cars are far easier to learn in; no panicking about what gear to be in or fear of stalling or rolling back. This allows you to focus better on the driving itself and possibly be a safer driver.
So if you are in a rush to get your driving licence because of school, university, work or other reasons. Possibly you've found learning in a manual car too difficult or perhaps you have a disability that stands in the way of changing gears - then learning in an automatic car may well be easier, cheaper and the quickest route for you to take to get your driving licence.