Which one, and whether either
Which is appropriate — or whether either is — depends on how much tooth structure remains, the condition of the gum and your bite.
How many appointments
Both usually require more than one appointment: preparation and measurement first, then fitting after the laboratory work.
Colour and shape
These are chosen together with you before the work begins. What is achievable differs from person to person and is decided at the examination, not in advance.
A crown or veneer does not remove the need for daily cleaning. The gum line around them still needs brushing and interdental cleaning.