Working on data migration projects to bring addresses from legacy databases into Salesforce we get this question about how to combine multiple street addresses to cater for the one street field that we have in Salesforce.
The answer is to use the CONCATENATE formula in Excel before importing the data.
Now the important part of concatenating is to make sure you add the line break between Street Line 1 and Street Line 2 by using CHAR(10).
Here is the summary of what you will need to do in Excel;
Imagine your have Street Line 1 in column A1 and Street Line 2 in column B2, you will need to add the third column called e.g. Combined Street and here is the formula to use: =CONCATENATE(A2,CHAR(10),B2)
Once this is imported your address field will look like this in Salesforce: