It depends on the type of certificate that you choose. For domain validated certificates, the certificate will be issued in minutes.
If you choose a business validated certificate it can take anywhere between a few hours to a few days to have the certificate issued (depending on how soon you submit the necessary documents to the Certificate Authority).
For EV certificates it usually takes 10 days for issuance and this also depends on how soon you submit the neccessary documents to the Certificate Authority.