A PC-relative expression or label is a symbol that represents the address of an instruction or literal data. It is represented in the instruction as the PC value plus or minus a numeric offset. The assembler calculates the required offset from the label and the address of the current instruction. If the offset is too big, the assembler produces an error.
For most instructions, the value of the PC is the address of the current instruction plus 4 bytes.
Your assembler might permit other syntaxes for PC-relative expressions, such as a label plus or minus a number, or an expression of the form