How to convert 8 bit binary to BCD using logical gates on multisim?
First of all, you can't convert 8 bits binary to EXACTLY one BCD, you'll need 3 BCD converters: the maximum value with 8 bits is 255, supposing you have unsigned numbers, so 3 digits are needed.
You have two choices:

Use asynchronous solution
There's an algorithm &quot;Double dabble&quot; that does the conversion from binary to BCD. You can start from here: Double dabble

Use synchronous solution
Use an 8×12 bits RAM. The address is the 8 bit value, the content of the cell, and hence the output, will be your BCD value.