DNS records can take on various functions. Accordingly, this question cannot be answered conclusively. However, we can explain the function of each type of DNS record to you. This article describes where you can change the DNS records.
A Records (Address Records)
These records assign an IP address to a name. This tells your browser, for example, that the myhosttech customer center, which is called up via https://myhosttech.eu, should be called up on the server with the IP address 188.8.131.52, and sends the request to this server accordingly.
MX records (Mail Exchange Records)
These records define to which server the mails of your domain should be forwarded. Either an IP address can be specified as the destination, or a name, for example mail.yourdomain.eu. You would then need a separate A record for the name mail.yourdomain.eu so that an IP address can be resolved for this name.