you can select Edit > Find and Replace > Other Options > Paragraph styles to locate where a style is used in a document. "Attributes" and "Format" dialog box will help us find character styles.

In LibreOffice Calc, you can use function REGEX for e.g.
Begins with 'ph' will be =REGEX(A1,"^ph")
Ends in 'E' will be =REGEX(A1,"E$")

To use a custom paragraph style for a heading, choose Tools - Chapter Numbering, select the level and choose a style in Paragraph Style box.
You can also choose number 1,2,3 for each level if you need 1.1, 1.1.1 numbering for heading.

Turn Off Grid Lines
If you want to turn off grid lines in LO Calc:
Tools > Options > LibreOffice Calc > View > Visual Aids > Grid Lines > Hide

Get the distinct values in calc
1) Select the column (or the list of data) that you want to process
2) Data > More Filters > Standard Filter
3) From Options choose "No duplications".

You can goto View - Styles and change "All Styles" to "Applied Styles" in the drop-down option.
You can Select everything (Ctrl+A) and then use Format > Clear Direct Formatting (Ctrl+M). That would wipe away all the styles, and would start you from a clean slate.

If your chapter titles are using the "Heading 2" Style:
1) View > Styles (F11)
2) In the sidebar, Right-Click > Modify on the "Heading 2" Style.
3) Go to the "Text Flow" tab.
4) On the right side:
5) Check the box for "Breaks > Insert".

This should automatically add a page break before every chapter.

Displaying Color in LO but Printing as White Page + Black Text:

1) Format > Page Style > Area > Color to assign the BG color you want.
2) Go to File > Printer Settings > Options.
3) Uncheck "Page background" and Check "Print in black".
4) Press "Save".

This will cause all files to print black text with no background color. You can also use "Save" + "Delete" button from Tools - opetions - Libreoffice - Application Colors.

1) Open a new file and set your font; Verdana; 18pt
2) File > Templates > Save as Template
3) Select > My Templates then tick the "Set as default template" box
4) Enter a name at the top then save and close the file.

The next time you open Writer, the settings should be in place.

The list of short english words written in Devanagari.

# egrep -x '.{1,2}' eng_words.txt
ऑन
ऑफ
ऑल
टी
टू
डे
डॉ
द
फी
लॉ
सन

CITI
Standard Chartered
HSBC
American Express

HDFC
ICICI
AXIS
INDUS IND
Kotak Mahindra
IDBI

SBI
Canara Bank
Vijaya Bank