An information adding method, comprising: performing, by a transmit end, polar code encoding on a first bit sequence, to generate an encoded second bit sequence; adding, by the transmit end, all of an identifier sequence to the second bit sequence, to generate a third bit sequence, wherein the identifier sequence is used to identify a terminal; and sending, by the transmit end, the third bit sequence, wherein the adding, by the transmit end, all of an identifier sequence to the second bit sequence, to generate a third bit sequence comprises: performing, by the transmit end, a scrambling operation on the second bit sequence by using all of the identifier sequence, to generate the third bit sequence, wherein the performing, by the transmit end, a scrambling operation on the second bit sequence by using all of the identifier sequence comprises: scrambling, by the transmit end, the second bit sequence by using all of the identifier sequence based on a specified mapping relationship, and wherein the scrambling, by the transmit end, the second bit sequence by using the all of the identifier sequence based on a specified mapping relationship comprises: sequentially scrambling, by the transmit end, the second bit sequence by using all of the identifier sequence through z times of repetition, wherein N=zT, wherein the encoded second bit sequence has a length of N bits, and the identifier sequence has a length of T bits, where z is a positive integer, and z>1, wherein the performing, by the transmit end, a scrambling operation on the second bit sequence by using all of the identifier sequence comprises: performing, by the transmit end, the scrambling operation on all of the second bit sequence by using all of the identifier sequence. performing, by a transmit end, polar code encoding on a first bit sequence, to generate an encoded second bit sequence; adding, by the transmit end, all of an identifier sequence to the second bit sequence, to generate a third bit sequence, wherein the identifier sequence is used to identify a terminal; and sending, by the transmit end, the third bit sequence, wherein the adding, by the transmit end, all of an identifier sequence to the second bit sequence, to generate a third bit sequence comprises: performing, by the transmit end, a scrambling operation on the second bit sequence by using all of the identifier sequence, to generate the third bit sequence, wherein the performing, by the transmit end, a scrambling operation on the second bit sequence by using all of the identifier sequence comprises: scrambling, by the transmit end, the second bit sequence by using all of the identifier sequence based on a specified mapping relationship, and wherein the scrambling, by the transmit end, the second bit sequence by using the all of the identifier sequence based on a specified mapping relationship comprises: sequentially scrambling, by the transmit end, the second bit sequence by using all of the identifier sequence through z times of repetition, wherein N=zT, wherein the encoded second bit sequence has a length of N bits, and the identifier sequence has a length of T bits, where z is a positive integer, and z>1, wherein the performing, by the transmit end, a scrambling operation on the second bit sequence by using all of the identifier sequence comprises: performing, by the transmit end, the scrambling operation on all of the second bit sequence by using all of the identifier sequence.