There are many people have already suggested you many platforms but I like to make sure few things before you are going to start using one/few of exchanges out of those suggestions.

You can choose an exchange which is available in your country like the exchanges are not available completely or restricting few features for some countries. You must make sure your selected exchanges providing all its services or all the services you are looking from an exchange. For example, you may prefer to have debit from an exchange but that exchange may not service it to your country.

You must be ready to clear KYC with all your government provided documents. Some exchanges are assuring about not requiring KYC for ever. So, you need to educate yourself like you are ready for KYC or not and its requirements and how to clear it.