Upon maturity, the principal may be returned to the linked account, or the certificate may be automatically renewed according to the issuance terms and your recorded instructions.
Key points
If automatic renewal occurs, it will typically be at the terms and rate in effect at the time of renewal, not necessarily the same yield as before.
Review your settings before the maturity date if you intend to use the funds or change the product.
The figures, fees and limits in this answer vary by bank and change over time — confirm them with your bank or the official source before acting.