Before you produce your Gerber files for manufacture ensure your silkscreen font size can be produced. This requires that you check the line widths of all silkscreen features, but the font line width and size needs checking and the text positioned appropriately.
The font features are in the Design Technology, with PCB view active select the Design Technology from Settings – Design Technology or the short cut Shift + T.
Select the “Text Styles” tab and adjust the required font ‘width’ and ‘line width’ to that required but exceeding the minimum requirements of your manufacturer.
Typical manufacturer requirements as detailed by Mint Tek are:
The values are adjusted by clicking on the values and inserting your required values as shown below:
The resulting PCB appears as follows after positioning and rotating the component references. These should be placed to ensure visibility when the components are mounted and preferably not overlapping any pad or areas where solder paste or soldering will occur, however most PCB manufacturers will also delete any silkscreen overlapping these areas but this will obviously obscure the text.
As a final check it can be useful to print a PDF at 100% scale to ensure legibility and positioning.
See also: How can I produce PDF files?