Help me understand the difference between a Common Lookup and Standard Lookup

Summary

Help me understand the difference between a Common Lookup and Standard Lookup

Content

Please help me understand the difference between a Common Lookup and Standard Lookups. I tried to follow the notes here but could not quite get much of it.

Help me understand the difference between a Common Lookup and Standard Lookup

https://docs.oracle.com/cd/E60665_01/globalcs_gs/FAIAM/FAIAM1453276.htm#FAIAM224997

I would be more interested to learn when to use a standard lookup.

Thanks

Mansur Aulam