Q: What does "pending approval" status mean without any comments and suggestion from editors before this status?

From your question, it is unclear at what stage of submission this status was indicated by the journal or how long after your submission this status appeared. Your question appears to indicate that no update was provided, i.e., any indication about peer reviewer assignment or the manuscript being under review. Occasionally, owing to glitches in the system, the submission status tracker might take longer to reflect the current status.

In some journals, “pending approval” indicates that the decision regarding your manuscript is pending approval from the Editor-in-Chief. The time taken for pending decisions varies by journal and editor. Please wait patiently for further updates on the status. If there is no change for over a month, you might need to write an email to the Editor-in-Chief to enquire about the status.

Read about tracking your manuscript status in journal submission systems here: Tracking your manuscript status in journal submission systems

Similar questions have been answered by us:

• What is the meaning of the status "Pending Approval"?
• What does the status 'Pending Approval' mean at Hindawi?

You may also find this handbook useful: Keep Calm And Wait: A Guide To Understanding Journal Statuses