If I buy the font folio, can I use ' ITC AVANT GARDE' FONT in commercial in perpetuity?
And if so, can I get any document work which includes 'Adobe give permission of use the font in commercial' or anything for guarantee our use?
All fonts in the Adobe Font Folio may be used by licensees for commercial work assuming that you are not distributing the font itself. You may print directly to a print device with the fonts. You may create PDF, EPS, or PostScript files with the font embedded within those files. There is no royalties associated with distributing those PDF, EPS, or PostScript files with the embedded font. However, what you cannot do is distribute the font files themselves to anyone who isn't themselves directly licensed for the fonts and you cannot use the fonts as “web fonts” (i.e., live content rendered in a browser using the fonts). You can display rasterized text using the fonts in a browser, though.
You don't need anything beyond the EULA for the Font Folio (that is on the Font Folio disk itself or may be downloaded from Adobe's web site.