B cell receptor and antibody are two types of immunoglobulin molecules that are associated with B cells. There are a few significant differences between them. 

B cell receptor  

B cell receptor (BCR) is a type of membrane-bound immunoglobulin molecule. It occurs on the surface of B cells and serves as a type of transmembrane protein. B cell receptors have a C-terminal hydrophobic region in the heavy chains. It also has another transmembrane domain for signal transduction in the B cell receptors. There are two types of B cell receptors – IgD and IgM. The main function of B cell receptor is to bind with a specific antigen to activate the B cell

Antibody

Antibody is a type of secreted immunoglobulin. It is produced by the B cell in response to specific antigen. Unlike B cell receptors, antibodies do not contain any transmembrane domains. There are five classes of antibodies – IgG, IgA, IgD, IgM, and IgE. The main function of antibodies is to bind to the antigen and elicit immune responses through various pathways. They are also responsible for recruiting other immune cells to destroy the invading pathogen.