What exactly do you mean by "link"? Do you want to display a custom property in a text field? Do you want to set a custom property via a text field?
When you are dealing with scripting in the PDF world, then JavaScript is what you would use. It's built into Adobe Acrobat, the free Adobe Reader and a number of 3rd party PDF viewers.
The following script for example will print all (even custom) info properties:
for (var i in info) {
console.println("info[" + i + "] = " + info[i]);
}
So, to get one of these properties into a field, create a text field and use the following as it's custom calculation script:
event.value = info["GTS_PDFXConformance"];
For e.g. a PDF/X compatible file, this might show "PDF/X-3:2002"
See here for more information about the info object: http://help.adobe.com/en_US/acrobat/acrobat_dc_sdk/2015/HTMLHelp/index.html#t=Acro12_MasterBook%2FJS_API_AcroJS%2FDoc_properties.htm%23TOC_info1bc-21&rhtocid=_6_1_8_23_0_20
Karl Heinz Kremer
PDF Acrobatics Without a Net
PDF Software Development, Training and More...
http://www.khkonsulting.com