A strong password has at least 12 characters and combines uppercase letters, lowercase letters, numbers and special symbols. Avoid dictionary words, names, or repeated patterns. Use a unique password for every account.
Generation happens entirely in your browser β nothing is sent to any server. The randomness comes from Math.random(), which is suitable for most non-cryptographic purposes. For cryptographic keys, use a dedicated tool with a CSPRNG.
Random Strings are often used to generate passwords, tokens, salt values, verification codes, etc. The stronger the randomness, the higher the security.