Using the Tor browser can make one's Internet usage absolutely anonymous. We recommend using Tor if nothing else (like a VPN) is used.
The below paragraphs contain links to outside websites and sources of data; we maintain that the individual must verify the links therein.
It is not the purview of this article to describe Tor at a technical level. With brevity in mind, one may simply understand Tor as a means of anonymizing one's Internet information (IP address, history, etc.). Tor is built atop the onion principle, which implies multiple layers of defense ("defense in depth", if one is familiar with some basic principles of cybersecurity). Servers accepting Tor requests are decentralized and voluntary. Once an Internet connection is made, said connection is routed through any number, and in any random order, of Tor servers, to the effect that the end server has no knowledge of the identity of the connected person. This can act to anonymize a user.
We present some concern that large agencies (like the FBI or CIA) may have "mapped" all routes through the Tor network, since these entities exclusively use Tor for their work. However, this cannot be verified fully. We maintain that the reader understand this, and be aware of it, but note that we do not view Tor as compromised. If one can tolerate the reduction in speed, we recommend Tor be used for everything.
The principles of DHitMA: Anonymity should be followed, even using Tor. We recommend using Tor exclusively for "sensitive" work, and another browser, like Brave, for regular work. We say this, only because Tor can be rather slow, since the routing process through the Tor network can take quite some time. Do not expect to use Tor to stream high-quality video at perfect speeds.
If the Tor browser is used, then a VPN is unnecessary if anonymity is desired. However, some individuals choose to layer Tor with a VPN. We do not recommend either solution over the other, except to say that the Tor browser, and VPN use, are quite slow to begin with, so layering a VPN on top of Tor will reduce speeds accordingly.
If one desires to maintain absolute anonymity, with no realistic hiccups, then review the no-fault scheme described in DHitMA: A Scheme for Maintaining Perfect Anonymity.
Tor and Emails
There are few Tor-friendly emails that remain free. Most email providers do not allow registration with a Tor IP, but do allow login once the account is created with a normal IP.