Please: do NOT laminate them - you won't be able to succesfully photocopy them later (because of the shine) and if the laminating machine breaks down you may destroy the document completely. Other don'ts: no sellotape - it leaves dark stains (see 1939 Register for examples of this) or metal paper clips - they go rusty.
There are several companies that supply archival-friendly (henceforth known as a-f) materials. For artifacts you can obtain a-f tissue paper to wrap them in and then store them in a-f boxes.
With documents there are "plastic" sleeves - these are designed to store postcards, photos, medals/coins, A5 & A4. They are created so that the chemicals in your documents' ink does not leach out and then get stuck to the plastic.
For birth/marriage/death certificates there are special sized ring binders with a-f sleeves and a-f card inserts so that you can have two certificates back to back in the same sleeve without touching each other.
These companies also supply cotton gloves for handling your items - if you so wish.
Here are some suppliers: https://genfair.co.uk https://genealogysupplies.com www.my-history.co.uk |