Use the # character to indicate a heading line:
You can customise the size of headings, as well as their color (and the color of the # symbol itself) from Soulver's styling preferences.
If you want Soulver to ignore numbers or calculations, put them inside a comment:
You can also add comments on the end of lines:
I spent $128 + $45 on clothes // on 10-02-2019 | $173.00
Hint: If there's a single number you want to exclude from an expression, you can also put it in parentheses, like this:
$699 (for iPhone 8) | $699