well if you have no extra information, then you can add name, score, strand column which are basically your column4, column5 and column6 by adding .(dot) for column4, 0(zero) for column5 and +(strand) for column6.
If you can give an example of what kind of data is available to you, I can modify my answer to have the correct name, score and strand.
MACS uses strand information (which would be in column 6) for the fragment size model it builds. If you want to use MACS and you expect your peaks to be narrow (i.e. you would want to use the model building step), I think you should try to get the strand information from whatever aligner you used into your bed file. Without knowing more, I can't help you with how to do that.
If you don't have the strand information (i.e. if you made them all + strand), you have to use the --nomodel option.