Favorite: Binance US Other options are Crypto.com, FTX and Coinbase
Your online account is an online wallet. Exodus.com is a very secure online wallet service. The most secure option is an offline wallet. Ledger.com has great products.
Tradingview is the best! A paid subscription is needed to utilize necessary indicators.
These are critical to understanding market sentiment and proper entry/exit positions. Moving Averages MACD Stochastic RSI
In regards to taxes, crypto is taxed like capital gains. IRS tax crypto tax regulations and guidelines here.
Recommended media worth following.