Visa- For Indians it is visa on arrival available for 30 days.
Currency- Idr comes in 100k,50k,10k,5k and 2k notes. Best to exchange INR to USD in India and then to IDR in BMC approved money exchanger outlets for safe and best rates. Rates are better in the city, so exchange a few dollars for taxi at the airport and rest when you reach the city.
Ubers and Grab taxis are available, but like in India face a lot of resistance from the local taxi providers. A reliable taxi service provider is the Blue Bird Taxi, a light blue cab, they offer metered rides. They aren't allowed to pick up rides from the airport arrival, so take the lift and move to the departure terminal and hail a blue bird which is dropping a customer from there. For full day trips, we used Kintamani Travels, both drivers were english speaking and very professional, contact Nyoman at firstname.lastname@example.org for any requirement.
Airport Taxis: 150k-200k to Seminyak, bargain and don't pay more than 150k. An Uber or Blue Bird is much cheaper, cost us 80k to reach Seminyak.
For exploring on your own, scooters are the best options, also Bali has left hand drive, making it easy for Indians. Many shops offer scooters for rental, ranging from 50-60k per day, you can bargain basis the number of days of your requirement. Make sure you wear your helmets.
License - International driving license is required, but not demanded by the shops renting out the scooters. Do bear in mind that foreigners are often stopped by the local cops, but we didn't face any such issues.
Petrol: Costs around 7-8k idr per litre
Season- Peak season is from July-August, but even in march there was significant crowds everywhere
Weather- Humid and hot with temperatures in 25-35 degrees. Make sure to carry sunscreen and hats especially if you plan to use scooters.