You can change the font size for the list windows in the native client. Right click on the list window's column headers and select the "Font Settings" menu item. The font typeface, style, and size can be configured from the displayed dialog box. This allows you to temporarily increase the font size for a presentation but then return to the regular font size later. http://help.seapine.com/helixalm/2017.2.0/client/Default.htm#User/ChangingListColumns.htm?Highlight=font%20settings
You can change the default font size for multi-line text fields via the Local Options. From the native client menu, select Tools >> Local Options. On the Local Options dialog, go to the Formatting category, check the "Override operating system default font size", and then select a specific font size. This will only affect multi-line text fields, like the Description field, and only affect text that does not have a specific font size selected by the user who added the text. http://help.seapine.com/helixalm/2017.2.0/client/Default.htm#ClientUser/SettingFormattingOptions.htm?Highlight=default%20font
You cannot currently change the font size for the view/edit windows. That is an open feature request.