There is often confusion around nameservers, A records, and where "pointing", "updating" etc should be done.
NOTE: We have two sets of nameservers, those for our DirectAdmin (dns1.vehost.co.za & dns2.vehost.co.za) clients and those for our cPanel (ns1.vehost.co.za & ns2.vehost.co.za) clients.
If you register a domain abc.co.za with VE Host, and the panel you're using is cPanel then the nameservers are ns1.vehost.co.za and ns2.vehost.co.za. If you are using DirectAdmin then the nameservers are dns1.vehost.co.za and dns2.vehost.co.za. Since the nameservers are with VE Host, this makes VE Host authoritative for abc.co.za which means that you can manage the DNS entirely from your VE Host client portal. In short, the place to where the nameservers are pointing is the place where you should create, update and delete DNS records. Examples of DNS records are: A, MX, CNAME, TXT, DMARC etc.
In the event where you registered abc.co.za with another web host, you could still update the nameservers to be ns1.vehost.co.za and ns2.vehost.co.za if you are using cPanel. If you are using DirectAdmin then you would update your nameservers to dns1.vehost.co.za and dns2.vehost.co.za. This would make VE Host authoritative for abc.co.za, thus allowing DNS management for abc.co.za through the VE Host client portal.
There might be a case where you want the website to be hosted with VE Host, but your might want your emails with another web hosting company. In such a case the starting point is to determine where you should change the DNS records to achieve this. This place is of course at the host where the nameserver (NS) records are pointing. For the purposes of this example lets assume the NS records are pointing to VE Host. Next, you'll login to your VE Host client portal and ensure that the A record is pointing to one of VE Host's IP addresses, these are by default setup so you shouldn't need to change anything here. Next, ensure that the MX record is pointing to the web hosting company where your emails are hosted.
As a rule of thumb the website is "hosted" and loads from the web host to where the A is pointing. The DNS is managed at the web host where the NS records are pointing