the enchants on the sword dont work because i bought it from a villager

Please clarify what you mean by “dont work”, as from what I can tell in the screenshot all the enchantments are present on thee bought sword. Please also provide a copy of the world.

the base damage of the iron sword is 6 but i have sharpness 3 and its still 6

how do i provide a copy of the world its my friend’s realm

After looking further, this issue actually duplicates https://mojira.atlassian.net/browse/MC-271840. The extra damage should still apply, it is just not shown currently.