EXEC sp_configure 'show advanced options', 1; RECONFIGURE;
EXEC sp_configure 'xp_cmdshell', 1; RECONFIGURE;

The procedure to achieve it is as follows:

Declare a variable of “table” type to save the output that returns the xp_cmdshell procedure (remember that it returns the result in several rows).
Dump the output of the command to the previous variable.
Concatenate the rows of the table, separated by a line break.
Encode the resulting string in Base64 and save it in a variable.
Generate the certutil command, appending the string with the result.
Execute it.