how to merge cell in excel?

You can combine two or more adjacent cells in a cell and display the contents of a cell in the merged cell. You can also combine the contents of multiple cells and display them in a cell. The fusion cell sorting functionality off.

You can separate (or divide) a cell that has been merged, but you can not divide a blank cell, not combined. You can, however, divide the contents of a cell without combining and distribute the content divided into other cells.
Merge Cells:
By combining two or more adjacent cells, the cells become a merged cell, and the content of the top left cell is shown in the center of the merged cell, as shown in the following example.
Only data for the top left cell of a selected range of cells remain in the merged cell. The data in other cells of the selected range will be deleted.

If you want to display data in the merged cell is not in the top left cell, do the following:
Select the data you want to be displayed in the merged cell, then click Copy on the Standard toolbar.
Select the top left cell of the range of adjacent cells that you want to merge, and then click Paste on the Standard toolbar.
Select the cells you want to combine.
NOTE The cells you select must be adjacent.

On the Formatting toolbar, click Merge and Center.
The cells are merged into one row or column, and the cell contents will focus on the merged cell.

Note If the Merge and Center button is unavailable, the selected cell may be in edit mode.To cancel the edit mode, press ENTER.

To change the text alignment in the merged cell, select the cell and click Align Left or Align Right on the Formatting toolbar.
Combine contents of multiple cells into one cell

You can use a formula with the ampersand (&) to combine text from multiple cells into one cell.

Select the cell where you want to merge the contents of other cells.
To start the formula, type = (
Select the first cell that contains the text you want to combine, type & "" & (with a space between the quotation marks) and then select the next cell that contains the text you want to combine.
To merge the contents of more than two cells, continue to select the cells, so be sure to write and "" and between selections. If you do not want to add a space between the combined type, and instead of & "" &. To insert a comma, type & "," and (with a comma followed by a space between the quotes).

To complete the formula, type)
To view the results of the formula, press ENTER.
Tip You can also use the CONCATENATE function to combine text from multiple cells into one cell.

Example
The following worksheet example shows what is available you can use. The example may be easier to understand if you copy a blank sheet.