There are 3 options for redirect:
1. Temporary HTML redirect
This will give the wrong impression to search engines and does not pass pagerank, but will allow you to track the stats of visitors being transferred from one site to the other. From an SEO perspective I wouldn’t recommend it on a temporary basis as it will probably affect the search engine rankings for your website regardless of whether you then switch it back or it becomes a permanent fixture.
2. 301 Permanent Redirect
This does exactly what it says on the tin, it sets up a permanent redirect to the new url (and you can tailor the landing pages individually to point at specific pages on the new website if needs be).
This style of redirect sends a header to the search engines saying the site has permanently moved from the old website domain (or web page) to the new domain url. It passes pagerank from the old page to the new page which is quite important for search engines, and eventually the search engines will stop indexing the old website and just index the new website.
3. Domain Redirect
A domain redirect is where we simply point the old domain at the new website however people finding the site through search engines will likely face a wall of 404 page not found errors and it could prove confusing, but it is possible to do a domain redirect and then handle 301 redirects individually on the new website (you would need to speak to your new hosting provider or web development team and ask them kindly to enable this).
Our recommendation would be option 2 from a search engine perspective as we can customise the 301 redirects, and get all of the pagerank transferred across, if you simply point the old domain at the new site you will get no benefits and potentially land visitors on a 404 page, temporary HTML redirects don’t pass juice and so are a bad idea from an SEO perspective.