Hello,
I saw the screenshot you added. To change the font-size and typography of the areas you specified. You need to go to Theme Settings >> Typography >> Advanced Typography >> Custom selector.
Screenshot for Clarification: https://www.screencast.com/t/sibbBnho
You can target the following classes respectively:
1) Searchbar:
.searchform.search-style-with-bg.woodmart-ajax-search .s
2) Accounts Button:
.woodmart-header-links.woodmart-navigation.menu-simple-dropdown.wd-tools-element.item-event-hover.my-account-with-text .wd-tools-text
3) Cart Price:
.woodmart-cart-subtotal
Result Screenshots: https://www.screencast.com/t/RnABWdNMOQ
https://www.screencast.com/t/B82Mrr6lC
https://www.screencast.com/t/d3HQRv34v
If you are still unable to change the typography of the areas then tell me then I will check it myself and help you out accordingly.
Best Regards.