You can buy travel insurance from whoever you want to. AIT offers the Travelex 360 policy attached to the email.
NOTE: Like most travel insurance policies, the Travelex policy does not cover COVID. If you want a policy that includes COVID coverage, you will have to find another policy. Be sure your own health insurance will cover you internationally.
If you want coverage through this Travelex policy, please add up your trip costs (flight & tours) and select the coverage amount you want from the table on the right of the chart below. AIT will include this in your invoice and it will be effective soon after you pay for it. Your policy will be provided to you with your tour packet.