How do we call upon His name?

How do we call upon His name?
BQ: Acts 22:16 says, "Now why do you delay? Get up and be baptized, and wash away your sins, calling on His name." We see that washing away sins is associated with being immersed/baptized and "calling on His name." (Tomorrow: saved?) 

Q: How does one "call on His name," and what does it mean? 
A: First, Acts 2:21 records, "And it shall be that everyone who calls on the name of the Lord will be saved." This is not something audibly done with the mouth, as in Romans 10:9, which isreferred to as "confession with the mouth," which leads "to salvation." So what is it?

In Acts 25:11, Paul "appealed" to Caesar: "I appeal to Caesar." This word is the exact same as in Acts 2:21 and 22:16. It is from "epiklaeo," to appeal, to call upon. We appeal to Him because of what we recognize Him to be: the One before Whom justice would be served, just as Caesar was on earth to Paul.  

So this is an "inquiry" (eperotema; closely related), which is ALSO the same as "an appeal," and we see it in 1 Pet 3:21, which says, "Corresponding to that, baptism now saves you-- not the removal of dirt from the flesh, but an appeal to God for a good conscience-- through the resurrection of Jesus Christ."

We can see from above that calling upon His name takes place with immersion. It's an appeal for a good conscience, and it washes away our sins. What a great thing to be able to make an eternal appeal to God! 
(PN141)