InDesign sets type by means of the Paragraph Composer setting. As you type, the text flows and then reflows to a settled condition when your typing is complete. This is normal behavior.
Make sure you are using Paragraph Styles to control your text. Don't merely manually dress the text from the top Control Panel only. It is the Paragraph Style that indents the paragraph by setting the First Line Indent amount. You do not indent either with multiple spaces nor a press of the tab key, as is done on a typewriter.
The Paragraph Style should be set to Align Left. It should have Hyphenation set to 9,3,4,1, 1p6, off, off, off. The Justification settings should be Word Spacing at 80/100/120; the Letter Spacing at -5/0/5%; and the Glyph Scaling at 95/100/105%.
If InDesign reflowing a paragraph somehow displeases you, you can edit the Paragraph style to use the Single Line Composer instead of the Paragraph Composer.