For CISA,
Mainly your concepts should be clear.
ISACA Review Manual & ISACA Q&A Database is must. (latest version of both)
In addition, you can attend virtual lectures of any classes.
Practice Q&A as much as you can.
ISACA local chapter conduct virtual classes for the same.
Also, there are many institutes providing virtual classes for it. Some of them are:
Simplilearn,
SprintZeal,
IEvision,
Delphi,
Mildain,
Infosectrain,
etc.
Also, from the experience of people, the Book of Hemang Doshi is also very helpful.