Getting your photo ready for print

Hi Guys,
I tried to find a different group to ask this, but I didn't see any that would technically fit, so I figured if anyone has any experience with this, it would be someone in here. I'm saving my files out for print. I'm using MpixPro and they require that you save out as a jpg with an embedded srgb color profile. In Photoshop, I was using the export command and saving out my jpgs. I had pulled in one of the files to try to resize/crop and went to the Image Resize... command and noticed that my ppi was at 72. It also does not keep the srgb color space with the image.This happened to every photo that I had that I used the Export... command on. I believe the acceptable standard for prints would require it to be at least 240ppi. The only way I could achieve this was to do use the Save as... command. It seems to keep my ppi at 300, per the original workspace and it does seem to embed the srgb color space. Have any of you noticed this? Is the Save as... command the only way to maintain the original ppi of a document or am I doing something incorrectly using the Export command? Any information would be appreciated. Thanks.