If you have GaussView, version 5 - there shouldn't be a problem, it reads CIF files as inputs.

If you don't have it, you have to convert the CIF file to a format Gaussian would read. A good format would be e.g. .mol2. You can do it easily in OpenBabel, or for example open the CIF file in CCDC Mercury and then save it as .mol2 file.

Hello Waqas.

Sometimes converting cif to mole is not a recommended method as you lose some critical information. Especially, the sig figs of bond length etc. (You can try with any cif file containing phenyl ring). As  Bartosz Trzaskowski mentioned, the best option if guessview, you can edit, modify or remove some solvent molecules if you don't want them. But if you don't have guessview, then best option is Chem3D. I think Quaid-I-Azam University department of Chemistry must provide you people Chem3D (Akhar Pakistan ki best university ha). Open it in Chem3D, go to calculations and directly make Gaussian input file (.GJF or .com file). It will save the real experimental geometry without any modification. You can modify this input (in term of basis or level of theory) anytime using Gaussview.

Hello Waqas Ali Shah,

Open the .cif file in Mercury 3.3 software program, then save as .sdf file. You can open it easily in GaussView.

I can mention another solution that works and it is verified since I use it all the time and it has worked every time it's a little bit tedious so bear with me. Open gauss view create any simple structure (for eg: H2O) and then save it (it saves by default as a gjf file) and open it using a notepad/wordpad and keep it aside. Now open your cif file in note pad/word pad and compare the two files and copy paste the lines instead of the H2O lines (co-ordinates and bonds). It might sound difficult but when you compare both the notepad files it is very easy and then once you change the lines, save as gjf file and then open it using gauss view, you'll get the structure properly.  Hope it helps. 

Hello

How are u? I get result on Chem-Bio Draw computer. I want to open that file on Gauss-View(Chemviz machine) I saved in Gaussian input file (gjf). Can u guide me How it will open.

Thanks