In the beginning all we had was photoshop.
You'd go through a PSD and cut it up any crazy colors or backgrounds or etc... and save them all to photos and rebuild the grid so to speak using a table with 0 for all spacing or borders or etc... If you were fancy, you'd do it with slices which allowed you to name each slice and save them in 1 shot.
Option 2 if you didn't have fancy backgrounds or fancy menu bars - you'd just use the tools you had. Click on a line of text - get the font size, weight, color - into css all that goes. Click on the ruler tool - 18 px from the left, 20 px from the top - into the css all that goes.
If someone sent me a PSD now a days, i'd do option 2 - if the site called for it, option 1 also probably.
We use Figma - it's nice. Click a design element, get its properties - into the css file it goes.
I personally don't let any tool export css for me - I want to pick and choose the properties and build the css file as I think is appropriate - making classes as generic as possible to be re-used elsewhere - so if Figma does that - news to me lol...
Not much has changed though - use the tools you have access to, get your measurements and properties and build the html / css appropriately.