Operations with aggregate functions - SQL Server

Firstly, to repeat a lot of my comments.

Don't use literal strings for aliases; this is a bad habit and it doesn't work as people think. Take the query SELECT [name] AS 'DatabaseName' FROM sys.databases ORDER BY 'DatabaseName'; This does not ORDER BY the column aliased as 'DatabaseName', instead it orders by the literal varchar value 'DatabaseName'; thus is has no order, as the literal value is the same for every row. Ideally, don't use object and aliases that require delimit identifying. If you must then either use T-SQL's delimit identify, brackets ([]), or the ANSI-SQL delimit identifier, double quotes (").

Next, you can't reference a column by it's alias in the same query scope apart from in the ORDER BY; SELECT 1 AS A, A + 1 AS B; will give an invalid column error, as the column A isn't defined. You would need to repeat the expression again to use that expression in the same scope. If you need to reference a column by its alias, you need to use a derived table or a CTE:

--Derived table
SELECT A,
       A + 1
FROM (SELECT 1 AS A) DT;

--CTE
WITH CTE AS (
    SELECT 1 AS A)
SELECT A,
       A+1 AS B
FROM CTE;

Finally, DateE BETWEEN '05/07/2022' AND '05/07/2022 23:59:59' is bad for a couple of reasons; it misses off the last second of the day, and its an ambiguous date format. Use >= and < logic and an unambiguous format; for T-SQL that is yyyyMMdd and yyyy-MM-ddThh:mm:ss(.nnnnnnn). So instead you have DateE >= '20220705' AND DateE < '20220706'.

Now, onto your problem. As I mentioned, there are a couple of options open to use. Personally, I would suggest just repeating the expressions here, as they aren't complicated:

SELECT NumeroD AS Bill, --Don't use literal strings for aliases
       Descrip1 AS ProductDescription, --Don't use object names/aliases that require delimit
       MAX(ExistAnt) AS [Ex. Act.],    --If you must, then use brackets ([]) or double quotes (")
       MIN(ExistAnt) AS [Ex. Act.],  --but, ideally use camelCase, PascalCase, or snake_case instead (I prefer PascalCase)
       --The above 2 columns have the same alias; that can't be right
       SUM(CASE WHEN TipoFac = 'A' THEN Amount
                WHEN TipoFac = 'B' THEN -Amount
           END) AS TotalAmount,
        CASE WHEN TipoFac = 'A' THEN (Amount*Price) END AS TotalSale,
        CASE WHEN TipoFac = 'A' THEN (Amount*Cost) END AS TotalCost,
        CASE WHEN TipoFac = 'A' THEN (Amount*Price) - (Amount*Cost) END AS TotalUtility, --Repeat the expression
        CASE WHEN TipoFac = 'A' THEN (((Amount*Price) - (Amount*Cost)) * 100) / (Amount*Price)  END AS PercentageUtil,
        NroLineaC,
        DEsComp
FROM dbo.SAITEMFAC --Always schema qualify your objects
WHERE DateE >= '20220705' AND DateE < '20220706' --Use better date boundaries, not BETWEEN
  AND codubic = '0010-01'
  AND CodItem = '11001'
GROUP BY Coditem,
         NumeroD,
         Descrip1,
         TipoFac,
         Cantidad,
         Precio,
         Costo;

If you "had to" reference them by their alias, or for more complicated expressions, I would use a CTE. This isn't needed for what you have here, but I'll show you anyway. As you have a nested reference, you'll actually need to use two CTEs:

WITH SalesCost AS(
    SELECT NumeroD AS Bill, 
           Descrip1 AS ProductDescription,
           MAX(ExistAnt) AS ExAct1,   
           MIN(ExistAnt) AS ExAct2, --These cannot have the same name in a CTE/Derived table
           SUM(CASE WHEN TipoFac = 'A' THEN Amount
                    WHEN TipoFac = 'B' THEN -Amount
               END) AS TotalAmount,
            CASE WHEN TipoFac = 'A' THEN (Amount*Price) END AS TotalSale,
            CASE WHEN TipoFac = 'A' THEN (Amount*Cost) END AS TotalCost,
            NroLineaC,
            DEsComp
    FROM dbo.SAITEMFAC --Always schema qualify your objects
    WHERE DateE >= '20220705' AND DateE < '20220706' --Use better date boundaries, not BETWEEN
      AND codubic = '0010-01'
      AND CodItem = '11001'
    GROUP BY Coditem,
             NumeroD,
             Descrip1,
             TipoFac,
             Cantidad,
             Precio,
             Costo),
Utility AS(
    SELECT Bill,
           ProductDescription,
           ExAct1,
           ExAct2,
           TotalAmount,
           TotalSale,
           TotalCost,
           TotalSale - TotalCost AS TotalUtility, --No need for the CASE here, as it's already handled
           NroLineaC,
           DEsComp
    FROM SalesCost)
SELECT Bill,
       ProductDescription,
       ExAct1,
       ExAct2,
       TotalAmount,
       TotalSale,
       TotalCost,
       TotalUtility,
       (TotalUtility * 100) / TotalSales AS PercentageUtility,
       NroLineaC,
       DEsComp
FROM Utility;