All digital images are Date and Time Stamped in the EXIF Metadata of the file. That is IF the camera has the correct Date and Time set in the firmware menu options.
Depending on the phone model the images created by it usually include the date and time in the file name (at least mine does).
If you are looking to place Date and Time Text on the image itself I don't think that is possible with LR. Not even with the Watermark option in the Export dialog.
I suggest you do a Google search for this and see if there are any programs for this or LR Plugins that might do that.