Arezzo Car hire for Tuscany

Per Google maps there are several rental car offices within a short walk of the Arezzo train station, including Avis & Budget.
Note the restricted operating hours - closed Sunday, open only from 9 AM to 1 PM on Saturday, and a 2 hour break between 1 and 3 every weekday.
You really should book an automatic if you're unfamiliar with driving on the right - will save you a lot of aggravation.
Per your other post (ie when you were going to start from Florence) any of the mapping apps will work fine. Both Google maps and Waze worked well for us in Italy. Navigating out of the city should be pretty straightforward, but do put your passenger to work assisting with signage, looking for conflicting traffic, watching out for ZTL signage, etc.
Driving gets pretty mellow once you get out of the city.
Using the street view feature on Google maps is always helpful for me in previewing my daily routes, and I find it particularly helpful in helping me get out of congested areas ... like the Arezzo city center.

Get off at Arezzo station. The train will stop only at that station.
There is Avis Budget across the street from the station.
Other major companies like Hertz or Europcar will require a taxi, although they are not far.
I’ve only used Europcar office there, but only because I wanted to change my car, which I ended up not being able to do because the customer who was supposed to return the large car I needed, decided to prolong their rental and no car was therefore available for the switch (which I eventually did in Venice).

So my story that year should warn you about the pitfalls of renting a car from small franchise offices in small cities, Their fleets are small, and the models available are limited. I don’t have a problem driving manual transmission (actually all my cars in California are stick and when in Europe I ask for manual because I prefer it) but if you need an automatic car, you have a better chance to actually get one in Rome. Automatic cars are not as popular as in America and are not always available especially for compact and economy models. Only about one third of new cars sold in Italy are automatic and mostly in the larger models.

Also you will have similar challenges even in large cities if you pick up your car at a small city office. In Rome the largest rental offices are at the airport, at the Termini station, and the central city offices on Via Sardegna (not far from the Spanish steps). In those you will find the greatest selection of models.

US drivers need an IDP to rent in Italy. Most navigation apps have NO knowledge of ZTL areas. Italian laws about some automatically included (partial) insurance can conflict with some "credit card" insurance requirements to "decline all coverages."

After I re-read your post, I only now realized that you may be from Down Under and not from America.
I should have guessed it from the use of the word “hire” rather than “rent” a car.

Getting out of town is easy enough, but use a navigator. Waze is the recommended navigator for Italy, as somehow it knows not to send you inside ZTL (restricted Limited Traffic Zones), and, most importantly it knows where the speed trap cameras are. That is particularly important in Arezzo where they placed a 30 km/h speed limit (18 mph) almost everywhere, a speed limit I find impossible to abide by, also because the locals (who know where the cameras are) will honk at you incessantly if you try. I’m sort of a local in Arezzo (my ancestors and most of my relatives are from that province and I go often) so I know where most cameras are, but I still rely on Waze for any new ones that might pop up from year to year.

And yes, I do recommend to drive on the right side of the road, even though you may not be used to it. If you don’t you will have to worry about much more than ZTL or speed violations. Also cars in Italy, like in the rest of continental Europe, have their instruments placed opposite to what you might be used to. Most importantly the steering wheel (the driver’s side) is on the left side, and you will need to change shifts using the right hand (in case you end up driving a manual transmission car). I know it takes a lot of concentration to drive on the opposite side of what you are used to, I’ve experienced that myself and almost had a head on collision in the Bahamas.

Thank you everyone for your helpful responses!
Yes we are from Australia . First time to Italy
Much appreciated !!