Quality of graphs made in Excel are not good enough to be published in journals. It will be helpful if anyone could suggest a simple and free software that produce good quality graphs. Thanks.
If I can ask a follow up question, why not? I have had Journal articles related to Journalism published with graphs from Excel—is there something in particular they’re looking for in the graph?
Not free, but I suspect provided by your institution if you have Excel: try Microsoft Word. Graphs are simple, straightforward but I haven’t had a complaint yet
Agree with Gregory. Excel has worked for me so far. You could also generate graphs using R if you are familiar with it, but am not sure if their quality would be much better than Excel.
Another option is Easel.ly. It's a website with data visualization templates: you can simply choose a template, input your data and it will generate the graph for you as an image file. A paid account provides better quality images, but even the free account's image quality is pretty good.
Popular choices from my field (physics) are Python with its MatPlotLib (https://matplotlib.org/) and Graphics Layout Engine (http://glx.sourceforge.net/).
Output images from graphs produced in excel are not satisfactory to be placed in a journal article. Quality (resolution) of graphs get reduced by significant amount. My field of research is in civil engineering, more particularly on geoenvironmental engineering, storm surge & coastal structures modelling.
Previously one could save Excel graphs as vector graphics if you first embed them into an empty word document and export it as a pdf file. It could then be cropped using an editor capable of dealing with vector graphics, such as GIMP, Photoshop, or Inkscape. Maybe with the current version of Excel it is possible also directly. This will remove problems with resolutions.
But in any case, if your research will involve anything more complicated than line or scatter plots or histograms, learning a script-based plotting tool will surely pay back the initial effort to learn it. The script will enable not only the graphs to be easily modified and reproduced for the same data, but allows the same design to be conveniently re-used for similar data as well.