ArcMap Desktop and ArcGIS Pro can export GeoPDFs but they are not supported in Esri mobile apps i.e. ArcGIS Field Maps. This makes no sense given that GeoPDFs are widely accepted in non-Esri GIS mapping mobile apps.
There are limitations with PDFs because spatial information is simplified to an image with a fixed resolution and cant be queried etc. However, GeoPDFs are small in file size, easy to generate and circulate to non-technical users that require a simple locality map for offline navigation.
Esri equivalents or workarounds are difficult to implement: i.e. TPK files (Tile Packages) are to too time consuming to generate. https://support.esri.com/en/technical-article/000021054 - This technical article explains the process of converting a PDF to GeoTiff, then generating a tile package. The problem with this process is that you end up with a file which is significantly larger than the original PDF file.
Another alternative is to use a MMPK (Mobile Map Package) but these files can end up being extremely large in size and are difficult to share via email. You can share MMPK files via Portal but this requires user training, download instructions and Portal access (Unless you tick the 'Enable anonymous use' during mmpk file generation, but this requires the Publisher extension $).
Please vote for this idea if you would like to help expand GeoPDF support across ArcGIS Field Maps and the Esri ArcGIS technology stack.
