Use Text to Columns
Select the names column
Go to Data > Text to Columns
Choose Delimited
Select Space as the delimiter
Click Finish
Use formulas
First name: `=LEFT(A1,FIND(” “,A1)-1)`
Surname: `=RIGHT(A1,LEN(A1)-FIND(” “,A1))`
Use Flash Fill
Type the first name in the next column
Start typing the surname in the next column
Press Ctrl+E to auto-fill
Use newer Excel functions
First name: `=TEXTBEFORE(A1,” “)`
Surname: `=TEXTAFTER(A1,” “)`