Placing files

[michael22530247qqui]

When I place a png  file I can resize it but not change the colors in it. 
and when I place an .ai file I can edit the colors and select sections  but I can;t resize it.
can you help?

[Mylenium]

AI is a vector program, so editing pixel data as in a PNG is limited. The rest is unclear since you have not provided any info on the artboard settings, the source of the imported files and so on. Likely you are simply not grouping your contents to be able to resize everything. Anyway, I would strongly suggest you actually read the online help since most of what you seem to have issues with is really basic stuff.

Mylenium

[Anna Lander]

Here are some useful help articles about the imported stuff in Illustrator 
Vector stuff and PSD files:
https://helpx.adobe.com/illustrator/using/importing-artwork-files.html

Raster images (e.g. PNG):

https://helpx.adobe.com/illustrator/using/importing-bitmap-images.html

What does the program say when you try to change the size of the imported AI file? It can forbid this operation if the final artwork size is going to be larger than the working area size.