Can my iPhone or iPad be infected with a virus?

Providing your iPad has been kept up-to-date with system software updates, you should not be overly concerned for your iPad being directly compromised by malware. Due to the sandboxed system architecture of iOS/iPadOS, unless jailbroken, your iPad is not susceptible to traditional malware infection per-se. However, as with all computer systems, there are still vulnerabilities and exploits to which you remain vulnerable. For older devices, no longer benefiting from regular security updates, the risk of an unpatched vulnerability being exploited increases.

Regardless of the installed version of iPadOS, there are useful mitigations that can be used to significantly reduce your exposure to risk.

Be wary of an often repeated myth that Apple devices are immune to malware; those that perpetuate this fallacy, perhaps with good intention, do not comprehend the broader threat landscape. Apple expend considerable resources in developing and issuing regular software security updates and patches for its products; if the myth had any substance, regular security updates would be unnecessary.

The majority of threats to which you will be invariably exposed will surface via web pages or embedded links within email or other messaging platforms. 

No. You do not have a virus if your device is not jailbroken. Describe the issue you are having and I'm sure someone will be able to help.