The function strcpy is a standard library function in the C programming language used to copy a string from one location to another. It takes two arguments: the destination string and the source string. The function copies the characters from the source to the destination until it encounters a null terminator, which marks the end of the string. Using strcpy requires caution, as it does not check for buffer overflows. If the destination string is not large enough to hold the copied content, it can lead to undefined behavior or memory corruption. Therefore, developers often prefer safer alternatives like strncpy.