Im using a Siteground account and im lack of space, so i need to only move the email to another host (Hostinger in this case), wich record should i change in DNS? Only the MX or should i add another one?
Thank you in advice!
You just need to make sure that all the records that Hostinger ask for are there. You will definitely need to change the MX record, but may also be using SPF, DKIM etc. that requires you to update TXT records. You should check with Hostinger what records they need.