Libre Office seems to be spontaneously changing font, format, and spacing. What am I missing?

When I create a document, I guess I expect it to stay with the same font, font size, formatting, etc. These spontaneous changes make almost double the work, in having to put documents back to the way I started with. This occurs in writing, particularly in moving lines and in cut-and-paste.
As for work flow, I’m almost entirely on woed documents. That is where the bulk of the problem happens.
I am using a Windows OS on a PC. Not sure what LO version I have; i didn’t download it.
Please? Anybody help?

That’s likely an indication of direct formatting, i.e. formatting document outside the style machinery.

Edit your question to give more detail on your workflow. Also, mention your OS and LO version.

Please choose a short title.

Done and done.

woed documents

What are woed documents?

WORD.Sorry, I have tendonitis. Not the best typist today.

Then the problem is almost inevitable. Work with ODT only and learn to use styles.