Big gap

Sometimes when you insert text between words there is a big gap. What should I do to avoid it?

@azamatik471 Could you please attach your input document and provide a simple code that will allow us to reproduce the problem? We will check the issue and provide you more information.
From the screenshot I can assume that the paragraph has Justify alignment. In this case MS Word distributes words in the line to line up them to both left and right sides. This might lead to increasing whitespaces between words. To avoid this you can specify Left paragraph alignment.