plasma is the whitish/clear part of the blood.

when a person is donating at a donation center the intake is the same, the screening process is the same regardless of if you are giving ....

whole blood (all 4 parts of the blood),
just platelets (clear disk shaped help with clotting and healing),
just plasma (the liquid part of the blood that has nutrients)
Just red blood cells (red disk like parts of the blood) or
white blood cells (leukocytes that fight infection)

most at regular city donation centers give plasma, or whole
red cross donation centers usually do whole blood
Hospitals take donations for all of the above.