A 301 redirect tells search engines that a URL has permanently moved to a new address. It passes most of the original page's authority (link equity) to the new URL.
A 301 redirect means "this page moved permanently here." It transfers SEO value to the new URL. Used for site migrations, URL changes or merging content.
Always use 301 for permanent changes.
Yes, nearly all of the link authority moves to the new URL.
301 for permanent moves, 302 for temporary ones.