Set custom BackgroundColor of a Excel sheet cell using epplus c#

Try this

Color colFromHex = System.Drawing.ColorTranslator.FromHtml("#B7DEE8");
ws.Cells["A1:B1"].Style.Fill.PatternType = ExcelFillStyle.Solid;
ws.Cells["A1:B1"].Style.Fill.BackgroundColor.SetColor(colFromHex);