insert grand total in chart

Hi gustavoluis ,

For this, you would have to make use a disconnected (no relationship with Facts/Dimension tables) table that contains all the unique items in a column (week number, etc) plus another row for Total and use that column in a visual.

Sample calculated table to create a disconnected table. 

Categories with total = 
VAR __CAT =
    ADDCOLUMNS ( DISTINCT ( Data[Category] ), "Sort", BLANK () )
VAR __TOTAL =
    ROW ( "Category", "Total", "Sort", 10 )
    //Sort column to be used to sort the Category column by where Total is the last one in ascending order. The rest are sorted alphabetically.
RETURN
    UNION ( __CAT, __TOTAL )

Sample measure to include the total.

Sum of Value with total = 
VAR __CAT =
    SELECTEDVALUE ( 'Categories with total'[Category] )
VAR __TOTAL =
    CALCULATE ( [Sum of Value], ALLSELECTED ( Data[Category] ) )
RETURN
    IF (
        __CAT = "Total",
        __TOTAL,
        CALCULATE (
            [Sum of Value],
            Data[Category] = SELECTEDVALUE ( 'Categories with total'[Category] )
        )
    )

sample result

sample pbix

https://drive.google.com/file/d/1oUR5D1YftbCs8gDLDnxYq_QjYJmKhqhM/view?usp=sharing 

Hi gustavoluis ,

Whether the advice given by danextian  has solved your confusion, if the problem has been solved you can mark the reply for the standard answer to help the other members find it more quickly. If not, please point it out.

Looking forward to your feedback.

Best Regards,
Henry