In this article I will show you how to write vertically in an Excel file. We will write like we write normally and then we will use different options to rotate the data as per the requirements.

Write any text in cell A1 normally:

write nomally

Then choosing the option Home > Alignment (select Orientation or ab->) to rotate it vertically:

Orientation

Select vertical text as shown below:

vertical text

It will turn the text to the Vertical Text form as shown below:

Vertical Text form

Similarly we can experiment with other options like:

Rotate text up

It will turn the text upside down starting from below:

Rotate text up

Rotate Text Down

It will turn the text upside down starting from above:

Rotate Text Down

Angle Clockwise

It will turn the text at 45 degrees as shown below:

Angle Clockwise

Angle Counter Clockwise

It will turn the text at 45 degrees as shown below:

Angle Counter Clockwise

I have added all types of the text types explained in the article. It will show all text forms in different cells:

all types of the text types explained

Further reading:
Cutting Pieces of Text After Particular Sign 
How to generate random text from the list? 
Import external data from text files