Sounds like you didn't enter the text in the text box.
You have to enter the text in the "Text:" field before clicking OK. Then the cross hair cursor has a box attached, in the size of the text and any left click places the text in the drawing.
There is also a "Text" field in the Tool Options bar, where you can enter or change the text while the tool is avtive.
See
https://docs.librecad.org/en/2.2.0_a/ref/tools.html#othersTo change the text after it is placed use the Properties tool. The Text window appear where you can change the text and its apperiance.
Otherwise the text size might be too small. Try with different height, e.g. 20 or even 200, just to see if it change anything.
Also Auto Zoom can help to find the text if it is too small.
Armin
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