Tor Browser on your normal computer is enough for most people. Two situations call for more or less.
Tails, for a stronger setup
Tails is a whole operating system that boots from a USB stick, routes everything through Tor, and forgets everything at shutdown. It closes the gap that Tor Browser leaves open, which is your normal machine remembering the session or some other program reaching the network outside Tor. Worth it if your threat model includes your own hardware being examined.
Phones, for convenience
Tor Browser for Android opens Awazon and works, but copying long addresses is fiddlier and the anonymity set is smaller. There is no genuine Tor Browser for iOS, because Apple forces one browser engine, so prefer Android or a desktop. Do the setup-heavy work on a desktop.
The rule
Match the effort to what you are protecting. Casual use, Tor Browser on a desktop. Higher stakes, Tails.