The grave is the beginning stage of Hereafter (Aakhirah). The grave of the believer is a garden from the Paradise, while the grave of the disbeliever is a part from the Hellfire.
Talqeen which is recited for very dead person mentions the main questions which are: Who is your Lord? Who is your prophet? Who are your Imams? etc.
The questions about the faith are the main questions in the grave. Nevertheless, our deeds will have an effect in out grave. Good deeds will have very good reflection in the grave, while bad deeds will have bad reflection as well.