If you are just getting started in crypto, I am guessing you want something that will allow you to see all of your holdings in one place and evaluate the performance of them. I have been using
https://www.cointracker.io for a while now and it has been very helpful for giving me information on all of my holdings. It supports a variety of coins, tokens, wallets, and exchanges. It also gives you an easy way to track and estimate your potential taxes. It is basically a read only overview though, so actual purchases and trades will have to take place outside the platform using something like Coinbase, Kraken, Binance, or Crypto.com. They have an app for mobile devices as well. You should check it out, it might not do everything you want, but it could be a good place for you to start.