Hello @Lugom1 ,
I assume you want to know how to enter tax when using a General Journal Entry. Create your expense lines to the appropriate expense accounts. Then add a line with your tax account (i.e. GST/HST Payable or PST Payable). Enter the appropriate amount of tax. Tab over to the column whose header is Sales Tax. Choose the appropriate tax code for that tax line.
If you do not tab over to the sales tax column and choose a tax code, even though you've used the correct G/L tax account, none of the tax entered in your JE will hit the tax reports. Using the Sales Tax Code in the JE is the only way your tax reports will be correct.
Good luck!