Supreetha J
Yes, mass of particle parcels should indeed be uniform.
Each parcel is representative of a fraction of the total continuous mass flow rate (in Steady tracking) and they are formed by grouping particles with similar characteristics and properties defined in the DPM.
For detailed information on setting initial conditions for the Discrete phase, kindly refer to the User's guide
If you are not able to access the link, please refer to this forum discussion:
Regarding Surface options, this could be because of older Fluent version and the options are listed on the bottom left of the image shared.
Thank you.