In March 2025, the FBI put out a warning against using online “PDF Converters”. There will be a whole host of these types of websites displayed if you web search for things like “PDF Converters”, "Shrink a large PDF", and so forth. I would NOT recommend web searching for PDF editing type apps. Ones that have been around for quite awhile are smallpdf.com, ilovepdf.com, rushpdf.com. There may be others that are also safe amongst all the scamming sites. If the sites have a commercial app and cost involved, they are probably okay.