To split a cell in half in Microsoft Excel, you can use the "Merge & Center" feature. Here are the steps:

1. Select the cell that you want to split in half.
2. Click on the "Merge & Center" button in the "Alignment" group on the "Home" tab.
3. This will merge the selected cell with the cell to its right, creating one large cell.
4. Type the text you want to appear in the left half of the cell.
5. Type a forward slash (/) to separate the two halves of the cell.
6. Type the text you want to appear in the right half of the cell.

For example, if you want to check "Yes" or "No" in the same cell, you could type "Yes/No" after merging and centering the cell. This will create two halves of the cell, with "Yes" on the left and "No" on the right. You can then select the appropriate half of the cell to enter your data.