I like to use the BestChange service. It is an informative service for cryptocurrencies. The interface of BestChange has informative icons, showing whether the exchanger has manual exchange, whether the rate is fixed or the verification required, etc. You can also read reviews by real clients to make an informed choice. Here I bought my first cryptocurrency, and then sold and changed. Also here I learned how can you convert bitcoin to cash https://www.bestchange.com/bitcoin-to-dollar-cash.html
You can study the information there and find answers to your questions.