How To Add New Custom Feilds

how do i add new custom feilds?

vendor = so i can remember who i am selling from,"carrot and ring band size","base metal"

and some others

all but the vendor need to be shown to the customer and be searchable

Is this difficult?

I am afraid, additional custom development is required to do it

To say the truth, it is better you can give more details.

Where should be placed these custom fields? Do you have any sample?

Best regards,