: What are good guidelines and practices for word emphasis? I struggle on what to highlight, and when to use quote marks. I also exaggerate specific words. Example: Please Sign-out and Click

This seems to be asking within the context of either a software medium or some instructional material referring to said software, so I'm answering from that perspective.
In these cases, it's helpful to print the actual text found on the button/link in question word-for-word, which you already seem to be attempting. That's a good start. Putting that text in quotes tells the viewer that that exact text is somewhere on the screen, making it easier for them to find what they need.
Alternatively, if this is being printed somewhere like a sign or an instructional pamphlet, you might consider using more generalized language. That way, if the program is tweaked in some way down the road and the specific text is altered, your instructions/information aren't necessarily out of date, forcing you to print new material. Also, if these instructions are to appear in multiple places, you would do well to make them all very similar (if not identical) to each other.
Aside from that, I would make a few alterations to keep things grammatically correct and internally consistent. The rest is largely personal preference.
Here are some examples of what you might try:

Please click on "Sign out," then click on "Delete my sign-in info" before logging back in.
Please sign out, then select the option to delete your login information.

Highlighting the button/link text in bold is another approach:

Please click Sign out, then click Delete my sign-in info before logging back in.

Personally, though, I usually prefer quotation marks.
Also, sometimes you will see verbs like "click" capitalized, but I don't recommend this; it's not necessary and sometimes actually adds confusion.
Finally, if this question does apply specifically to a software medium, there is also an SE site dedicated to user experience topics (in case you weren't already aware).

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To create effective signage or instructions, always start with correct language.

I am answering for English language works. There will be some differences in other languages.

In your case, you overuse capitals. I also changed "and" to "then" to emphasize the order. Your starting sentence should read:

Please sign out then click delete my sign in info before logging back in.

Anything that is an exact quote should go into quotation marks.

Please sign out then click "delete my sign in info" before logging back in.

Or with a hyphen, if that is how it appears on the computer.

Please sign out then click "delete my sign-in info" before logging back in.

This is correct and good enough.

Another way you might want to create emphasis is to change the order. Think about the starting point for your readers. What seems the most important to me is you want to say "hey, if you're thinking of logging in, check first that you've done these things after your last session." So you might want to put that first.

Before logging in, please sign out from your previous session then click "delete my sign-in info".

You can also highlight things by making them a separate line. Or a larger font. All caps. Or bold. Italics can be a softer form of bold, but I would not use them for that on a sign or in important instructions. It's too easy to miss it. But you can use italics to mark exactness or something official.

You can also highlight that "this applies to you" line, then make the subsequent steps super clear.

BEFORE LOGGING IN


Sign out from your previous session
Click "delete my sign-in info"

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