Here's the command line I've used in my script to preprocess my data (DNA paired-end reads). By preprocess I mean adapter removal, trimming low quality bases and reads and N-bases. Also if there's anyone who can suggest some articles/document that could be helpful to better understanding the analysis and customize my fastp command. I also add --correction option to made some correction by using overlapping (--overlap_len_require = 30 bases by default).

 # Exécuter fastp
        echo " Fastp preprocessing with $SAMPLE..."
        fastp \
            -i "$R1_FILE" -I "$R2_FILE" \
            -o "$trimmed_r1" -O "$trimmed_r2" \
            --html "$html_report" --json "$json_report" \
            --detect_adapter_for_pe \
            --qualified_quality_phred 20 \
            --average_qual 20 \
            --length_required 50 \
            --n_base_limit 5 \
            --cut_front \
            --cut_tail \
            --cut_window_size 4 \
            --cut_mean_quality 20 \
            --trim_poly_g \
            --poly_g_min_len 10 \
            --trim_poly_x \
            --poly_x_min_len 10 \
            --correction \
            --thread 8

Please use ADD REPLY/ADD COMMENT when responding to existing posts. SUBMIT ANSWER is for NEW answers for the original question.

As others have indicated don't overthink this part of analysis. You don't need to change default parameters unless you have a very specific reason to do so (e.g. your data has bad qualities going in).

Strictly speaking you don't need to scan/trim (strictly needed, if you are going to do de novo work, to remove extraneous sequence). Aligners will generally handle extraneous sequence by "soft-clipping". But scanning/trimming is fine to do for peace of mind.